Action Observation for Neurorehabilitation in Apraxia

Abstract

Neurorehabilitation and brain stimulation studies of post-stroke patients suggest that action-observation effects can lead to rapid improvements in the recovery of motor functions and long-term motor cortical reorganization. Apraxia is a clinically important disorder characterized by marked impairment in representing and performing skillful movements [gestures], which limits many daily activities and impedes independent functioning. Recent clinical research has revealed errors of visuo-motor integration in patients with apraxia. This paper presents a rehabilitative perspective focusing on the possibility of action observation as a therapeutic treatment for patients with apraxia. This perspective also outlines impacts on neurorehabilitation and brain repair following the reinforcement of the perceptual-motor coupling. To date, interventions based primarily on action observation in apraxia have not been undertaken.

Keywords: action execution; action recognition; apraxia; mirror activity; neurorehabilitation.

Figure 1

Hypothetical model for performing and recognizing a transitive action [adapted from (54) and (55)]. Failures in performing or recognizing gestures may occur because of damage at any stage in the directional flow between perceiving (input) and performing (output) the action. The observation of a video clip or a real demonstration of action can have a positive effect on the selection and retrieval of the correct movement. In figure the example of grasping a cup of coffee. After the correct visual identification of the object as a cup, patients with apraxia have a difficult retrieval of the correct action associated with that object. When an incorrect movement is performed, a discrepancy occurs between the (correct) action observed on the model and the perception of own (incorrect) performed gesture. Combining motor training and action observation may enhance the relearning of daily actions and strengthen the visuo-motor coupling.